Polymerization of oxirane monoepoxides using an organometallic compound with a phenolas cocatalysts



United States Patent 3,398,119 POLYMERIZATION 0F OXIRANE MONOEPOX- IDESUSING AN ORGANOMETALLIC COM- POUND WITH A PHENOL AS COCATALYSTS KennethT. Garty, Somerville, and Thomas B. Gibb, Jr.,

Murray Hill, N.J., assignors to Union Carbide Corporation, a corporationof New York No Drawing. Filed July 1, 1959, Ser. No. 824,192 19 Claims.(Cl. 26047) This invention relates to the polymerization of oxiranemonoepoxide monomers. More particularly, this invention relates to animproved method of polymerizing oxirane monoepoxide monomers wherebyrelatively high conversions of monomer to polymer are effected inrelatively short periods of time.

Polymerization of oxirane monoepoxides in the presence of anorganometallic compound, such as dibutyl zinc, which serves as acatalyst for the polymerization reaction, has been found to be desirable'as the polymers produced are hard, tough solids Which are useful in themanufacture of various shaped articles and in the preparation of filmmaterial which can be used in the manufacture of bags, wrappingmaterial, and the like. Moreover, the organometallic compound remainingin the polymer at the termination of the polymerization reaction can beconverted into an inert, non-deleterious residue, which can be left inthe polymer if so desired, by a simple operation wherein the polymer iscontacted with water or an alcohol such as ethyl alcohol. Consequently,solid polymers produced by polymerizing 'an oxirane monoepoxide in thepresence of an organometallic compound do not require any elaborate andtime consuming purification operations in order to remove catalystresidue therefrom.

The extensive use of organometallic compounds as catalysts for thepolymerization of oxirane monoepoxides to produce solid polymers hasbeen seriously limited, however, clue to the relatively long periods oftime required in order to obtain any significant polymer yields. Inaddition, it has not been possible to obtain reproducible yields ofsolid polymer using organometa-llic compounds as catalysts. Yieldsobtained have varied from batch to batch and have been relatively small.

The present invention provides for the production of oxirane monoepoxidepolymers by polymerizing a monomerio oxirane monoepoxide and mixturesthereof in the presence of an organometallic compound and also in thepresence of a controlled amount of a phenol which acts 'as a promoterfor the polymerization reaction, whereby relatively high yields ofmonomer to polymer are effected in a short period of time. Moreover, thepresence of a controlled amount of a phenol in the polymerizationreaction allows for reproducibility of polymer yields.

The amount of phenol employed in the polymerization reaction can varyfrom about 0.01 to about 2.5 moles per mole of the organometalliccompound. Optimum results are achieved at a mole ratio of phenol to theorganometallic compound of about 0.75:1 to about 1:1.

Any monohydric or polyhydric phenol, free of interfering functionalgroups such as an ester group, an acid group, an aldehyde group, and anamino group, can be used as a promoter for the polymerization of anoxirane monoepoxide in accordance with the present invention.Illustrative of such phenols are phenol, o-cresol, m-cresol, p cresol, ochlorophenol, m chlorophenol, p chlorophenol, a-naphthol, fl-naphthol,p-ethylphenol, thiophenol, selenophenol, p-hydroxydiphenyl,o-hydroxydiphenyl, o-cyclohexylphenol, p-cyclohexylphenol; polyhydricphenols such as catechol, hydroquinone, hydroxyhydroquinone,phloroglucinol, resorcinol and pyrogallol;

3,398,119 Patented Aug. 20, 1968 the dior polynuclear phenols such asthe bisphenols described in the Bender et a1. United States Patent2,506,- 486 and polyphenylols such as the novolak condensation of aphenol and a saturated or unsaturated aldehyde containing an average offrom 3 to 20 or more phenylol groups per molecule (cf. Phenoplasts by T.S. Carswell, published 1947 by Interscience Publishers, New York).Examples of suitable polyphenylols derived from a phenol and anunsaturated aldehyde such as acrolein are the triphenylols,pentaphenylols and heptaphenylols described in application Ser. No.368,514, filed July 16, 1953, and copending application Ser. No.422,275, filed Apr. 9, 1954, b A. G. Farnham, now Patent No. 2,801,989.

The phenols may contain alkyl or aryl ring substituents or halogens, asexemplified by the alkyl resorcinols, the tribromoresorcinol and thediphenols containing alkyl and halogen substituents on the aromatic ring(Bender et al., US. Patent 2,506,486).

The polyhydric polynuclear phenols can consist of two or more phenolsconnected by such groups as methylene, alkylene, ether, ketone, orsulfone. The connecting groups are further exemplified by the followingcompounds: bis( p hydroxyphenyl) ether, bis(p hydroxyphenyl)ketone,bis(p-hydroxyphenyl)methane, bis(p-hydroxyphenyl)dimethyl methane,bis(p-hydroxyphenyl)sulfone, and the like.

The term polymer as used herein is intended to encompass homopolymers,as well as copolymers and interpolymers produced by polymerizing amixture containing two or more monomeric oxirane monoepoxides.

Organometal'lics which can be employed as catalysts for thepolymerization of oxirane monoepoxides to produce solid polymers arecompounds whose compositions can be represented by the formula:

wherein Me is a metal of Group II of the Periodic Table, i.e.,beryllium, magnesium, calcium, zinc, strontium, cadmium, barium,mercury, and radium; and wherein R and R are hydrocarbon radicals suchas alkyl, aryl, aralkyl, a'lkaryl, and cycloalkyl. Particularlydesirable organometallics are those compounds having the structuralformula noted above wherein R and R are hydro carbon radicals havingfrom 1 to 10 carbon atoms and being free from olefinic and acetylenicunsaturation.

Representative R and R radicals include, among others, methyl, ethyl,propyl, isopropyl, n-butyl, isobutyl, Z-ethylhexyl, dodecyl, octadecyl,phenyl, tolyl, xylyl, benzyl, phenethyl, phenylpropyl, phenylbutyl,cyclopentyl, cyclohexyl, cycloheptyl, 3-propylcyclohexyl, and the like.

Illustrative of organometallic compounds which can be used as catalystscan be noted diethyl zinc, dipropyl zinc, di-n-butyl zinc, dioctadecylzinc, dicyclohexyl zinc, diphenyl zinc, di-o-tolyl zinc, diethylmagnesium, di-n-butyl magnesium, dioctyl magnesium, diphenyl magnesium,diethyl beryllium, di-n-butyl beryllium, diethyl cadmium, dipropylcadmium, diisoamyl cadmium, diphenyl cadmium, and the like. Theonganometallics are known compounds and can be prepared according to themethods described in Berichte 63, 1138 (1934); 59, 931 (1926).

The organometallic compounds are generally used in catalytic amounts,that is, in amounts sutficient to catalyze the polymerization of oxiranemonoepoxides to solid polymers. The actual quantity of organometalliccom-- tended to encompass those compounds having a single terminal epoxygroup, i.e.:

l CHr-O- which are free of all other interfering functional groups suchas an ester group, an acid group, an amino group, and an aldehyde group.

Among such oxirane monoepoxides can be mentioned the epihalohydrins,such as l,2-epoxy-3-chloropropane, 1,2-epoxy-3-bromopropane, and thelike; the olefin oxides, such as 1,2-epoxyethane, 1,2-epoxypropane,1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane,cyclopentene oxide, cyclohexene oxide, 1,2-epoxyphenyl-ethane, 1,2-epoxyp methylphenylethane, 1,2- epoxy-o-chlorophenylethane, and the like;epoxyalkyl ethers, such as those having the structural formula wherein Ris a hydrocarbon radical such as alkyl, aryl, alkaryl, aralkyl, and thelike, and wherein R is a saturated aliphatic hydrocarbon radical.Particularly desirable polymers are those produced by polymerizing amonomer having the structural formula noted above wherein R containsfrom 1 to 4 carbon atoms and -R' is a phenyl or alkyl substituted phenylradical wherein the alkyl substituent contains up to 12 carbon atoms.Illustrative radicals for R include, among others, methylene, ethylene,propylene, butylene, hexylene, octylene, and the like. Representativeradicals for R include, among others, phenyl, 2-, 3-, and4-methylphenyl, 4-isopropylphenyl, 4- tertiarybutylphenyl,4-octylphenyl, ethyl, propyl, butyl, amyl, and the like.

Suitable epoxyalkyl ethers include the following: 1,2- epoxyS-phenoxypropane, 1,2-epoxy 4-phenoxybutane, 1,2-epoxy-5-phenoxypentane,1,2-epoxy-6-phenoxyhexane, 1,2-epoxy-3-(o-methylphenoxy propane,1,2-epoxy-3- (mmethylphenoxy propane, 1,2-epoxy-3- (p-methylphenoxy)propane, 1,2-epoxy-3-(o-isopropylphenoxy)propane, 1,2- epoxy3-(p-tertiary butylphenoxy)propane, l,2-epoxy-3-(p-octylphenoxy)propane, 1,2-epoxy 3-(o-chlorophenoxy)propane, 1,2-epoxy3-(o-chlorophenoxy)propane, 1,2-epoxy-3-(2,4 dimethylphenoxy)propane,1,2-epoxy-3- (2,3 dimethylphenoxy)propane,1,2-epoxy-3-(2,6-dimethy-lphenoxy)propane, 1,2-epoxy-3-(2chloro-4-methylphenoxy)propane, 1,2-epoxy-3-(o amylphenyDpropane, 1,2-epoxy 4 (o-methylphenoxy)butane,l,2-epoxy-4-(2,4-dimethylphenoxy)butane, 1,2-epoxy 4(2,5-dimethylphenoxy)butane, l,2-epoxy-4-(2,4 dichlorophenoxyybutane,1,2-epoxy 4 (2,S-dichlorophenoxybutane, 1,2-epoxy-6- phenoxyhexane,1,2-epoxy 6-(2,3-dibromophenoxy)hexane, and the like.

The polymerization reaction is conducted by charging an oxiranemonoepoxide monomer or mixture of monomers, an organometallic compoundand a controlled amount of a phenol in a reaction vessel and generallysubjecting the reaction vessel to heat. Actually, the temperature atwhich the polymerization reaction is conducted can be varied over a widetemperature range, from about 0 C. to about 200 C., and, if desired,even higher. A temperature in the range of about 60 C. to about 175 C.is most preferred.

It is also preferred to conduct the polymerization reaction in thepresence of an organic diluent which is nonreactive with respect to themonomer, catalyst, and polymer, is a solvent for the monomer andcatalyst mixture, but a non-solvent for the polymer. During thepolymerization reaction, particularly whenever about 50 percent or moreof the monomer is converted to the polymer, the reaction mixture becomeshighly viscous. If a diluent is not present, it is difiicult to removethe heat of reaction which, if not removed, might cause undesirable sidereactions to occur. In addition, the use of a diluent facilitatesremoval of unreacted monomer from the polymer.

Illustrative of suitable organic diluents can be noted the aromatichydrocarbons, such as benzene, chlorobenzene, toluene, xylene, and thelike; cycloaliphatics, such as cyclopentane, cyclohexane, isopropylcyclohexane, and the like; alkoxy compounds, such as methoxybenzene andthe like; the dimethyl and diethyl ethers of ethylene glycol, propyleneglycol, diethylene glycol; aliphatics, i.e., hexane.

The diluent can be added prior to the commencement of the polymerizationreaction or during the polymerization reaction in amounts of from about5 to parts by weight per parts by weight monomer and diluent.

The polymerization reaction is preferably conducted under an inertatmosphere, e.g., nitrogen, and can be under atmospheric,sub-atmospheric, or super-atmospheric pressures.

The time required to polymerize an oxirane monoepoxide to produce asolid polymer will vary and depend upon a number of factors such as thetemperature at which the polymerization reaction is being conducted, theamount of and nature of the organometallic catalyst used, and also uponthe nature of the monomer employed. Using a phenol as a promoter inaccordance with the present invention, relatively high yields of polymerhave been obtained in as short a time as four hours.

The crude product resulting from the polymerization reaction usuallycontains, in addition to the solid polymer, some unreacted monomer, andalso catalyst residue. Removal of the unreacted monomer and catalystresidue can be accomplished by any convenient manner. If desired, thecatalyst residue can be left in the polymer after first treating thepolymer with water or an alcohol, such as ethyl alcohol. For instance,when dibutyl zinc is the catalyst used and it is desired to allow thecatalyst residue to remain in the polymer, the polymer is convenientlytreated with ethyl alcohol whereby the catalyst is converted to itsoxide, which oxide is inert and does not have any deleterious effect onthe polymer. The ethyl alcohol is driven from the polymer by applyingheat thereto. When it is desired to remove both unreacted monomer andcatalyst residue from the polymer produced, as for examplepoly(1,Z-epoxy-3-phenoxypropane), the crude product is dispersed in amixture of acetone and hydrochloric acid, the dispersion is thenfiltered, thereby obtaining the polymer as a filtercake and, ifnecessary, then washing the polymer with small amounts of ethyl alcoholto obtain a white colored solid. Unreacted monomer and catalyst residuecan be removed from a polymer such as poly(l,2-epoxyethane) bydissolving the crude product in ethyl alcohol, filtering oil thecatalyst residue, concentrating the solution to remove the alcohol andrecovering the polymer. In general, it is desirable to remove theunreacted monomer from the crude product as the polymer recoveredexhibits enhanced thermal and dimensional stability.

The percent conversion of monomer to polymer as noted herein wasdetermined by removing the unreacted monomer and catalyst residue fromthe polymer, drying the polymer to a constant weight at a temperature offrom about 50 C. to 60 C. under a pressure of 25 mm. Hg, weighing thepolymer, dividing the weight of the polymer by the weight of the monomercharged, and multiplying by 100.

In the following examples, which are illustrative of the presentinvention and not intended to limit the scope thereof in any manner, thereduced viscosity measurements, which are a measure of the molecularweight, were made as follows.

A 0.05 gram sample of polymer was weighed into a 25 ml. volumetric flaskand p-chlorophenol containing 2 percent by weight pinene added thereto.The flask was heated for 30 minutes in an oil bath maintained at C. withintermittent swirling. After solution was complete, additionalp-chlorophenol containing 2 percent by weight pinene was added toproduce a 25 ml. solution while RV= do where t is the efliux time forthe solvent t is the effiux time for the polymer solution is theconcentration of the solution in terms of grams of polymer per 100 ml.of solution.

Example 1 To each of two Pyrex glass tubes which had been flushed outwith nitrogen gas there was charged 8 grams of1,2-epoxy-3-phenoxypropane and a solution of 0.128 gram of dibutyl zincin 12 ml. of toluene. To one of the tubes there was also added 0.066gram of phenol. Both tubes were provided with a nitrogen gas atmosphere,sealed, and heated at 90 C. for 16 hours in an air circulating oven.Each tube was then broken open and the contents thereof were transferredto a Waring Blendor using 200 ml. of a mixture (50-50 on a volume basis)of acetone and toluene acidified with 5 ml. of 1 N hydrochloric acid.After thorough agitation in the Waring Blendor, the mixture was pouredinto ethyl alcohol. The amount of ethyl alcohol was 100 times the volumeof the mixture. The polymer precipitated out of the ethyl alcohol andwas recovered as a filter cake. The polymer was then washed with smallquantities of ethyl alcohol, dried at 60 C. for 24 hours under apressure of 25 mm. Hg and then dried an additional 24 hours at atemperature of from 40 C.-60 C. and a pressure of 25 mm. Hg.

The percent conversion of monomer to polymer, the mole ratio of phenolto dibutyl zinc, the reduced viscosity of the polymer obtained, and theamount of catalyst, i.e., dibutyl zinc, used are noted in the tablebelow.

Control 1 Mole ratio of phenol to dibutyl zinc 0 1:1 Percent by weightcatalyst 1. 6 1. 6 Percent conversion 3 92 Reduced viscosity 3. 7 5. 6

Example 2 To each of two Pyrex tubes which had been flushed out withnitrogen gas there was charged 8 grams of 1,2- epoxy-3-phenoxypropaneand a solution of 0.128 gram of dibutyl zinc in 12 ml. of toluene. Toone of the tubes there was also added .066 gram of phenol. Both tubeswere provided with a nitrogen gas atmosphere and heated for 88 hours inan air circulating oven. A white colored polymer was recovered from eachtube in a manner described in Example 1.

Control 1 Mole ratio of phenol to dibutyl zinc 0 1:1 Percent by weightcatalyst 1. 6 1. 6 Percent conversion 13 99 Reduced viscosity 4. 7 5. 2

6 Example 3 To each of two Pyrex tubes which had been flushed out withnitrogen gas there was charged 8 grams of 1,2-epoxy-3-phenoxypropane anda solution of 0.128 gram of dibutyl zinc in 12 ml. toluene. To one ofthe tubes there was also added .066 gram phenol. Both tubes wereprovided with a nitrogen gas atmosphere and heated for four hours in anair circulating oven. A white colored polymer was recovered in a manneras described in Example 1.

Control 1 Mole ratio of phenol to dibutyl zinc 0 1:1 Percent by weightcatalyst 1. 6 1. 6 Percent conversion 0. 6 40 What is claimed is:

1. Method for the production of a polymer of an epoxide compound whichcomprises contacting a monomeric oxirane monoepoxide, which is free ofester, acid, amino and aldehyde groups, with at least about 0.01 percentby weight, based on the weight of said oxirane monoepoxide, of anorganometallic compound having the formula:

wherein R and R are hydrocarbon radicals and Me is a metal of Group IIof the Periodic Table, and with from about 0.01 to about 2.5 moles of aphenol, which is free of ester, acid, amino and aldehyde groups, permole of said organometallic compound, whereby said oxirane monoepoxidepolymerizes to form a polymer.

2. Method as defined in claim 1 wherein the temperature at which saidoxirane monoepoxide is polymerized is from about 60 C. to about C.

3. Method as defined in claim 1 wherein the said organometallic compoundis used in an amount of from about 0.01 to about 12 percent by weightbased on the weight of the said oxirane monoepoxide.

4. Method as defined in claim 1 wherein the said organometallic compoundis dibutyl zinc.

5. Method as defined in claim 1 wherein the said oxirane monoepoxide is1,2-epoxy-3-phenoxypropane.

6. Method as defined in claim 1 wherein the temperature at which thesaid oxirane monoepoxide is polymerized is from about 0 C. to about 200C.

7. Method as defined in claim 1 wherein the said organometallic compoundis used in an amount of from about 0.1 to about 3 percent by weight,based on the weight of said monoepoxide.

8. Method as defined in claim 1 wherein said monomeric oxiranemonoepoxide is a member selected from the group consisting ofepihalohydrins, olefin oxides, and epoxy alkyl ethers of the structuralformula:

CHz-CHR-OR 0 wherein R is a hydrocarbon radical and R is a saturated,aliphatic hydrocarbon radical.

9. Method as defined in claim 3 wherein the said phenol is used inamounts of from about 0.75 to about 1 mole, per mole of the saidorganometallic compound.

10. Method for the production of a polymer of an epoxide compound whichcomprises contacting at a tem-v perature of from about 0 C. to about 200C. a monomeric oxirane monoepoxide, which is free of ester, acid, aminoand aldehyde groups, with from about 0.01 to about 12 percent by weight,based on the weight of said monoepoxide, of an organometallic compoundhavin the formula:

wherein R and R are hydrocarbon radicals and Me is a metal of Group IIof the Periodic Table, and with from about 0.01 to about 2.5 moles of aphenol which is free of ester, acid, amino and aldehyde groups, per moleof wherein R and R are hydrocarbon radicals and Me is a metal of GroupII of the Periodic Table, and with from about 0.01 to about 2.5 moles ofa phenol, which is free of ester, acid, amino and aldehyde groups, permole of said organometallic compound, whereby said oxirane monoepoxidepolymerizes to form a polymer.

12. Method for the production of a polymer of an epoxide compound whichcomprises contacting a monomeric oxirane monoepoxide which is free ofester, acid, amino and aldehyde groups, at a temperature of from aboutC. to about 200 C., in the presence of an organic diluent, with fromabout 0.01 percent by weight to about 12 percent by Weight, based on theWeight of said monoepoxide, of an organometallic compound having theformula:

wherein R and R are hydrocarbon radicals having from 1 to carbon atomsand being free of olefinic and acetylenic unsaturation, and from about0.01 to about 2.5 moles of a phenol, which is free of ester, acid, aminoand aldehyde groups, per mole of said organometailic compound wherebysaid oxirane monoepoxide polymerizes to form a polymer.

13. Method as defined in claim 12 wherein the said oxirane monoepoxideis polymerized at a temperature of from about 60 C. to about 175 C.

14. Method as defined in claim 12 wherein the said organometalliccompound is used in an amount of from about 0.1 to about 3 percent byweight based on the Weight of the said monoepoxide.

15. Method as defined in claim 13 wherein the said phenol is used in anamount of from about 0.75 to about 1 mole, per mole of saidorganometallic compound.

16. Method as defined in claim 13 wherein the said phenol is used in anamount of 1 mole per mole of said organometallic compound.

8 a 17. A method for the production of a solid polymer of an epoxidecompound which comprises contacting under polymerizing conditions amonomeric oxirane monoepoxide free of interfering functional groups witha polymerization catalyst consisting of a dialkyl zinc compound and apolyhydric phenol which is free of interfering functional groups,wherein the polyhydric phenol is present in an amount of about 0.2 toabout 1.2 moles per mole of the dialkyl zinc compound.

18. Method for the production of a solid polymer of an epoxide compoundwhich comprises contacting a monomeric oxirane mondepoxide free ofinterfering functional groups with a polymerization catalyst consistingof (1) an organomagnesium compound of the formula:

wherein R and R are hydrocarbon radicals free of olefinic and acetylenicunsaturation and (2) a polyhydric phenol free of interfering functionalgroups, wherein the polyhydric phenol is present in an amount of 0.02 to1.4 moles per mole of the organomagnesium compound.

19. A method for the production of a solid polymer of an epoxidecompound which comprises contacting under polymerizing conditions amonomeric oxirane monoepoxide free of interfering functional groups witha polymerization catalyst consisting of a dialkyl zinc compound and aphenol which is free of interfering functional groups, wherein thephenol is present in an amount of about 0.2 to about 1.2 moles per moleof the dialkyl zinc compound.

References Cited UNITED STATES PATENTS 2/ 1958 Parry et al 2602 1/ 1959Stewart et a1. 2602 OTHER REFERENCES WILLIAM H. SHORT, Primary Examiner.

T. PERTILLA, Assistant Examiner.

1. METHOD FOR THE PRODUCTION OF A POLYMER ON AN EPOXIDE COMPOUND WHICHCOMPRISES CONTACTING A MONOMERIC OXIRANE MONOEPOXIDE, WHICH IS FREE OFESTER, ACID, AMINO AND ALDEHYDE GROUPS, WITH AT LEAST ABOUT 0.01 PERCENTBY WEIGHT, BASED ON THE WEIGHT OF SAID OXTRANE MONOEPOXIDE, OF ANORGANOMETALLIC COMPOUND HAVING THE FORMULA: